1. Field of the Invention
The present invention relates to a method of receiving charge, a method of controlling charge, a charge control unit and charging equipment, for charging a battery in a device mounted with battery such as an electric automobile.
2. Description of Related Art
Recently, because of an increasing concern about environmental aspects, an electric automobile and a hybrid vehicle have been widely used as a vehicle discharging less exhaust gas. Such a vehicle is equipped with a battery which supplies an electric power to a motor so that the vehicle runs by the motor as a driving source. Accordingly, when a charge amount of the battery is lowered as running the vehicle, it is needed to charge the battery at a charging station or the like placed at a corner of a street at all such times (see Japanese Laid-Open Patent Publication Nos. 2010-28913, H07-115732, 2006-20438, 2006-262570 and S54-101526).
Although a technology for quick charging has been developed, under the present circumstances, it needs a long time to charge a battery. Hereby, when a vehicle occupies a charging station, other users have to wait their turn, resulting in causing the significant inconvenience. Further, the time required for the full charging of a battery is different depending on the battery residual quantity when the charging starts. Therefore, users can not know when the vehicle during charging completes the charging, which is a factor for spoiling the convenience of the users. In order to solve such inconvenience, a technology disclosed in Japanese Laid-Open Patent Publication No. 2010-28913 has been proposed.
As shown in FIG. 30, charging equipment 81 disclosed in Japanese Laid-Open Patent Publication No. 2010-28913 comprises a charge converter device 82 which converts the voltage acquired from the system to output a predetermined DC voltage, and a plurality of user operation units 84 connecting a vehicle 83 to the charge converter device 82 when charging. The charge converter device 82 comprises a power conversion unit 85 which converts a commercial power source to a DC power source, and a switching circuit 86 which distributes the DC power outputted from the power conversion unit 85 to a specific user operation unit 84. Herein, the user operation unit 84 corresponds to a so called charge terminal, in which a power supply plug is arranged at the end of a charge cable.
When a vehicle 83 is parked at a parking lot, a power supply plug of the user operation unit 84 is connected with the inlet of the vehicle 83 for charging the battery thereof. At that time, the charge converter device 82 connects the switching circuit 86 to the user operation unit 84 which is connected with the vehicle 83, thereby to connect the power conversion unit 85 to the user operation unit 84 in use. As a result, by a DC voltage from the power conversion unit 85, a DC current flows into the vehicle 83 through the user operation unit 84 in use, to charge the battery of the vehicle 83.
Here, the charging equipment 81 disclosed in Japanese Laid-Open Patent Publication No. 2010-28913 only performs a switching operation, in which one power conversion unit 85 is connected to a user operation unit 84 by a switching circuit 86. Accordingly, only one vehicle 83 can be charged by one charge converter device 82. That is, only one-to-one charging is available. Therefore, if a vehicle 83 is being charged, other vehicles can not be charged until the vehicle 83 completes the charging. Meanwhile, when a plurality of charge converter devices 82 are provided, a plurality of vehicles may be charged. However, this is not realistic because the costs required for preparing the charge converter devices 82 increase.